One critic says it's comparable to a couple days' salary for the company's CEO.

The Sierra Club's David Rogers said Friday the penalty is less than a slap on the wrist for the country's No. 2 electricity company, which generated $23 billion in revenue last year.

A spokeswoman for the state environmental agency would not explain whether officials were restricted from imposing a larger penalty, but said the amount was much larger than is typical. Duke Energy had agreed to pay $84,000 in January.

Duke Energy spokeswoman Paige Sheehan said the deal paves the way for the permitting needed for work toward closing the sites.